--- orig/gfx/layers/basic/X11BasicCompositor.cpp	2015-09-04 22:21:08.037174995 +0200
+++ patched/gfx/layers/basic/X11BasicCompositor.cpp	2015-09-04 22:21:03.833776657 +0200
@@ -130,6 +130,7 @@ X11BasicCompositor::EndFrame()
 {
   BasicCompositor::EndFrame();
   XFlush(DefaultXDisplay());
+  fprintf(stderr, "XFlush(DefaultXDisplay())");
 }
 
 } // namespace layers
